epj, our very own forum member has written an article on this very subject. I would think his post carries a little weight!
It is true that wheel weights are a bit hard to come by now a days, but they can be had!
I have NEVER had a bullet that was too big EVER lead a barrel no matter how hard it was, NEVER!
There is another forum that is a better help on the subject of cast boolits than the castboolits forum,
NRA - IHMSA Handgun, Rifle, Air Pistol Silhouette Shooting. The Excitement Of Reactive Steel Targets At The Los Angeles Silhouette Club
There are three sub-pages to look at:
Cast bullet reference on lead alloy's, min / max pressure, lube, shrinkage,
Cast Bullets For Beginner And Expert - Joe Brennan
Glen E. Fryxell, Cast bullets and firearm information and history
The castboolits forum is a GREAT place to gather with other casters, don't get me wrong, I'm a member there. Like here though, opinions can get in the way and make it difficult to weed out the unbiased advice.
Get into casting. Even if it sits on the shelf until you HAVE to have bullets and can't purchase them, know how to do it.
Wheel weights can be shot at as cast sizes and tumble lubed with Lee Liquid Alox or White Label Lube's Liquid Xlox. Water quenching can get the BHN, Brinell Hardness, up into the 30BHN range. Quite hard enough for some rifle work, way hard enough for any pistol work!
I have launched my homecast boolits to 1800fps with no leading sizing to .002" over bore diameter and BHN in the 15 - 18BHN range. Accuracy suffered over 1600fps but no leading. This was achieved with conventional lube from White Label, (BAC or Carnuba Red) or Lyman's Orange, in either the 45Colt Puma or a Marlin 1894 in 44Mag.
The same boolits from handguns are in the 1400fps range and again, no leading. From straight wheel weights to wheel weights with a little Linotype added, to water quenched wheel weights, all with no leading, period.
Now, I have had leading, don't get me wrong. 9mm, never did work that one out! Almost any cast from commercial casters to varying degrees. Simply cast too hard and too small, usually.
There are two hardness testers that are popular. Lee makes one, go to their website, and LBT makes one that seems to be easier to use @ $100.
To avoid what some have mentioned about not being able to guarantee hardness, you can buy a tester, cast some "test boolits" let them sit a day or two and test for hardness. If they are too soft, add tin (from lead free solder) or Linotype (from a scrap yard or metal supplier) or water quench.
Lots of choices and information, Dave. I hope it doesn't overwhelm you. If you get nothing else from the post though, take the exhortation to cast seriously. You won't be disappointed that you did.
If you need more information/help, feel free to PM me. I'll help all I can.